In general, various technologies for forgery prevention have been provided in order to prevent copied/forged products such as a generic drug, fake liquor, and counterfeit money. Conventional technologies for preventing forgery include a Moire pattern (an interference pattern with a wave pattern which is generated by overlapped dots or lines with geometrically regular distribution, if forgery is performed using a copying machine, a partial color change and a watered mark are generated due to an interference phenomenon), an intaglio press, a latent image (a printing technology in which cutting is performed by differentiating a direction of a printing area and a configuration of a part where there is no pattern so that a character or a pattern is hidden, and thus the character or the pattern appears in a certain direction or a method), an optically variable device (an element for preventing forgery in which a shape or a color changes depending on a viewing angle, such as hologram or Kinegram in a foreign banknote in which a shape and a pattern changes depending on the viewing angle), a watermark (as a motif or a character that appears by light and shade caused by thickness difference between a thin part and a thick part of a sheet for preventing forgery, a pattern such as a design and a letter which is viewed translucently or more darkly when a paper is viewed while being penetrated by bright light), and a security fiber (as a fine fiber inserted to a sheet, it has various functions that assign unique characteristics such as a color, a size, a property, a shape, an optical property, and a magnetic property, and is also used as a device sensing element).
However, a technique for preventing forgery incorporated with more complicated and various techniques have been required since the conventional technique is easily reproduced/forged by similar techniques. Therefore, the present invention introduces various characteristics in a complicated manner to enhance technology barriers against forgery, and achieves a method for manufacturing a composite film for preventing forgery that can be easily detected by a magnetic property without special analyzing equipment.